Collision of two spin-polarized fermionic clouds
Collision of two spin-polarized fermionic clouds
复制标题
两个自旋极化费米子云的碰撞
DOI：
10.1103/physreva.84.051605
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发表时间：
2011
影响因子：
2.9
通讯作者：
Goulko O
中科院分区：
文献类型：
--
作者：
Goulko O
通过对玻尔兹曼方程的模拟，我们研究了两个自旋极化的费米云在简谐陷阱中的碰撞。正如在最近的实验中观察到的，我们发现了三种截然不同的行为模式。对于弱相互作用，云会相互穿透。如果互动增加，它们会以指数级接近彼此，而对于强烈的互动，它们会反弹几次。我们由此证明，所有这些现象都可以使用半经典碰撞方法来复制，并且这些行为的变化与不断增加的碰撞率有关。然后，我们证明了弹跳区中云的振荡是量子气体中一种不寻常的情况的例子：集体模之间的非线性耦合，即自旋偶极子模和轴向呼吸模，这是由碰撞所强制的。我们还确定了作为平衡系统最终温度的函数的反弹频率。
We study the collision of two spin-polarized Fermi clouds in a harmonic trap using a simulation of the Boltzmann equation. As observed in recent experiments, we find three distinct regimes of behavior. For weak interactions the clouds pass through each other. If interactions are increased they approach each other exponentially and for strong interactions they bounce off each other several times. We thereby demonstrate that all these phenomena can be reproduced using a semiclassical collisional approach and that these changes in behavior are associated with an increasing collision rate. We then show that the oscillation of the clouds in the bounce regime is an example of an unusual case in quantum gases: a nonlinear coupling between collective modes, namely, the spin dipole mode and the axial breathing mode, which is enforced by collisions. We also determine the frequency of the bounce as a function of the final temperature of the equilibrated system.